Twitter Link Grabber Nikestore

I'm looking for a program that works specifically with Twitter and Nikestore.com.

On certain dates, Nike tweets out a link at a certain time to one or more of its shoes for customers to purchase. I'd like the program to be able to click the link that was tweeted by Nike's Twitter account (as soon as it's tweeted, the speed of the program is most important), select a shoe size (user customizable), click "Add to Cart", and go to the "Checkout" screen automatically. The program must be able to perform these steps as quickly and efficiently as possible.

To better understand how the program should work, please check out @Nikestore's Twitter account, click on one of the links, and analyze how their "add to cart"/checkout system works.

If you have any questions, feel free to ask!

Additionally, I need this program to work with Mac OS X.

I am on a budget and am not looking to spend $200+. However, I am willing to test out the script to verify that it works and make payments. I need this before this Saturday if possible. Thank you!

Here is a more precise description. It is a repost.The program, while running will need to complete the following

1). Follow a twitter account i.e @NikeStore official account.

2). Recognize a incoming tweet from @NikeStore with a twitter link to the product.(i.e. The LeBron X ‘Home’ is now available http://bit.ly/VLIX5T )

3). Automatically open the twitter link (i.e. http://bit.ly/VLIX5T which directs the user to the nikestore.com website where the sneaker is located)

4). Program needs to add a specific size (which must be editable) and quantity (needs to be editable also), and adds it to the cart, and then it automatically begins the checkout on the offical NikeStore link page.